Anionic vinyl/dicarboxylic acid polymers and uses thereof

ABSTRACT

Biodegradable anionic polymers are disclosed which include recurring polymeric subunits preferably made up of vinylic and dicarboxylic monomers such as vinyl acetate or vinyl alcohol and maleic anhydride, itaconic anhydride or citraconic anhydride, or combinations thereof. Free radical polymerization is used in the synthesis of the polymers, which are then hydrolyzed to replace ester groups with alcohol groups. The polymers may be complexed with ions and/or mixed with fertilizers or seed to yield agriculturally useful compositions. The preferred products of the invention may be applied foliarly, to seeds, to fertilizer, or to the earth adjacent growing plants in order to enhance nutrient uptake by the plants.

RELATED APPLICATION

[0001] This is a division of application Ser. No. 09/562,519 filed May1, 2000.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention is broadly concerned with novel anionicsubstantially biodegradable and substantially water soluble polymers andderivatives thereof which have significant utility in agriculturalapplications, especially plant nutrition and related areas. Moreparticularly, the invention is concerned with such polymers, as well asmethods of synthesis and use thereof, wherein the preferred polymershave significant levels of anionic groups. Additionally, the preferredpolymers also include significant levels of alcohol groups. The mostpreferred polymers of the instant invention include recurring polymericsubunits made up of vinylic (e.g., vinyl acetate or vinyl alcohol) anddicarboxylic (e.g., maleic acid, itaconic acid, anhydrides, and otherderivatives thereof) moieties. The polymers may be complexed onto ionsand/or mixed with or coated with phosphate-based fertilizers to provideimproved plant nutrition products.

[0004] 2. Description of the Prior Art

[0005] Lignosulfonates, polyacrylates, polyaspartates and relatedcompounds have become known to the art of agriculture as materials thatfacilitate nutrient absorption. All of them suffer from significantdisadvantages, which decrease their utility in comparison to the artdiscussed herein and limit performance.

[0006] Lignosulfonates are a byproduct of paper pulping; they arederived from highly variable sources. They are subject to large,unpredictable variations in color, physical properties, and performancein application areas of interest for this invention.

[0007] Polyacrylates and polymers containing appreciable levels thereofcan be prepared with good control over their composition andperformance. They are stable to pH variations. However, polyacrylateshave just one carboxylate per repeat unit and they suffer from a verysignificant limitation in use, namely that they are not biodegradable.As a result, their utility for addressing the problems remedied by theinstant invention is low.

[0008] Polyaspartates are biodegradable, but are very expensive, and arenot stable outside a relatively small pH range of about 7 to about 10.They usually have very high color, and incorporate amide groups, whichcauses difficulties in formulating them. Additionally, polyaspartateshave just one carboxylate per repeat unit and are therefore not a partof the present invention.

[0009]Russian Journal of Applied Chemistry, 24(5):485-489 (1951) teachesthe preparation of maleic anhydride-vinyl acetate copolymers in benzeneand acetone with benzoyl peroxide initiators. It further discloses theaddition of above copolymers to water, wherein the polymer graduallyself-hydrolyzes to a complex mixture containing units of maleic acid,vinyl alcohol, vinyl acetate, lactones, free acetic acid, and otherspecies. Deficiencies of this teaching include undesirable presence oflactone, which decreases number of dicarboxylic groups. In addition, nouse for polymers is taught or suggested.

[0010] U.S. Pat. Nos. 3,268,491 and 3,887,480 teach preparation ofmaleic acid-vinyl acetate copolymers in water-based solutions usingredox-based initiators in a certain pH range. The approaches describedin these patents are highly problematic. Only redox-type initiators areclaimed to be useful. A fixed pH range restricts the practice. Only anarrow range of copolymers composed exclusively from the monomers ofmaleic acid and vinyl acetate are taught. The process of U.S. Pat. No.3,268,491 is deemed to be non-commercial by U.S. Pat. No. 3,887,480which described improved processes but uses over 17% by weight of redoxinitiator; such processes are very wasteful, have high environmentalimpact, and are not cost effective.

[0011] U.S. Pat. Nos. 5,191,048 and 5,264,510 teach copolymerization ofacrylic acid, maleic acid, and vinyl acetate with subsequent hydrolysisby base. Again, several important deficiencies are evident. Among theseare the exclusive use of base hydrolysis and preferred embodiments ofinvention incorporating monocarboxylic acids. Only terpolymers aredisclosed. Furthermore, the intended uses of the compositions are veryrestricted and in no way teach, suggest or imply utility of theenumerated and contemplated compositions for the purposes of the presentinvention.

[0012] It will thus be seen that the prior art fails to disclose orprovide polymers which can be synthesized using a variety of monomersand techniques in order to yield end products which are substantiallybiodegradable, substantially water soluble, and have wide applicabilityfor agricultural uses.

SUMMARY OF THE INVENTION

[0013] The present invention overcomes the problems outlined above andprovides a new class of anionic polymers having a variety of uses, e.g.,for enhancing takeup of nutrient by plants or for mixture withconventional phosphate-based fertilizers to provide an improvedfertilizer product. Advantageously, the polymers are biodegradable, inthat they degrade to environmentally innocuous compounds within arelatively short time (up to about 1 year) after being in intimatecontact with soil. That is to say that the degradation products arecompounds such as CO₂ and H₂O or the degradation products are absorbedas food or nutrients by soil microorganisms and plants. Similarly,derivatives of the polymers and/or salts of the polymers (e.g. ammoniumsalt forms of the polymer) also degrade within a relatively short time,during which significant fractions of the weight of the polymer arebelieved to be metabolized by soil organisms.

[0014] Broadly speaking, the anionic polymers of the invention includerecurring polymeric subunits made up of at least two different moietiesindividually and respectively taken from the group consisting of whathave been denominated for ease of reference as A, B and C moieties.Thus, exemplary polymeric subunits may be AB, BA, AC, CA, ABC, BAC, CAB,or any other combination of A moieties with B and C moieties. Moreover,in a given polymer different polymeric subunits may include differenttypes or forms of moieties, e.g., in an AB recurring polymeric unitpolymer, the B moiety may be different in different units.

[0015] In detail, moiety A is of the general formula

[0016] moiety B is of the general formula

[0017] and moiety C is of the general formula

[0018] wherein R₁, R₂ and R₇ are individually and respectively selectedfrom the group consisting of H, OH, C₁-C₃₀ straight, branched chain andcyclic alkyl or aryl groups, C₁-C₃₀ straight, branched chain and cyclicalkyl or aryl C₁-C₃₀ based ester groups (formate (C₀), acetate (C₁),propionate (C₂), butyrate (C₃), etc. up to C₃₀), R′CO₂ groups, and OR′groups, wherein R′ is selected from the group consisting of C₁-C₃₀straight, branched chain and cyclic alkyl or aryl groups; R₃ and R₄ areindividually and respectively selected from the group consisting of H,C₁-C₃₀ straight, branched chain and cyclic alkyl or aryl groups; R₅, R₆,R₁₀ and R₁₁ are individually and respectively selected from the groupconsisting of H, the alkali metals, NH₄ and the C₁-C₄ alkyl ammoniumgroups, Y is selected from the group consisting of Fe, Mn, Mg, Zn, Cu,Ni, V, Cr, Si, B, Co, Mo, and Ca; R₈ and R₉ are individually andrespectively selected from the group consisting of nothing (i.e., thegroups are non-existent), CH₂, C₂H₄, and C₃H₆, at least one of said R₁,R₂, R₃ and R₄ is OH where said polymeric subunits are made up of A and Bmoieties, at least one of said R₁, R₂and R₇ is OH where said polymericsubunits are made up of A and C moieties, and at least one of said R₁,R₂, R₃, R₄ and R₇ is OH where said polymeric subunits are made up of A,B and C moieties.

[0019] As can be appreciated, the polymers of the invention can havedifferent sequences of recurring polymeric subunits as defined above(for example, a polymer comprising A, B and C subunits may include theone form of A moiety, all three forms of B moiety and all three forms ofC moiety). In the case of the polymer made up of A and B moieties, R₁-R₄are respectively and individually selected from the group consisting ofH, OH and C₁-C₄ straight and branched chain alkyl groups, R₅ and R₆ areindividually and respectively selected from the group consisting of thealkali metals.

[0020] The most preferred polymers of the invention are made up ofrecurring polymeric subunits formed of A and B moieties, wherein R₅ andR₆ are individually and respectively selected from the group consistingof H, Na. K, and NH₄ and specifically wherein R₁, R₃ and R₄ are each H,R₂ is OH, and R₅ and R₆ are individually and respectively selected fromthe group consisting of H, Na, K, and NH₄, depending upon the specificapplication desired for the polymer. These preferred polymers have thegeneralized formula

[0021] wherein R₅ and R₆ are individually and respectively selected fromthe group consisting of H, the alkali metals, NH₄ and C₁-C₄ alkylammonium groups (and most preferably, H, Na, K and NH₄ depending uponthe application), and n ranges from about 1-10000 and more preferablyfrom about 1-5000.

[0022] For purposes of the present invention, it is preferred to usedicarboxylic acids, precursors and derivatives thereof for the practiceof the invention. For example, terpolymers containing mono anddicarboxylic acids with vinyl esters and vinyl alcohol are contemplated,however, polymers incorporating dicarboxylic acids were unexpectedlyfound to be significantly more useful for the purposes of thisinvention. This finding was in contrast to the conventional teachingsthat mixtures of mono and dicarboxylates were superior in applicationspreviously suggested for mono-carboxylate polymers. Thus, the use ofdicarboxylic acid derived polymers for agricultural applications isunprecedented and produced unexpected results. It is understood thatwhen dicarboxylic acids are mentioned herein, various precursors andderivatives of such are contemplated and well within the scope of thepresent invention. Put another way, copolymers of the present inventionare made up of monomers bearing at least two carboxylic groups orprecursors and/or derivatives thereof. The polymers of the invention mayhave a wide variety of molecular weights, ranging for example from500-5,000,000, more preferably from about 1,500-20,000, dependingchiefly upon the desired end use.

[0023] In many applications, and especially for agricultural uses, thepolymers of the invention may be mixed with or complexed with a metal ornon-metal ion, and especially ions selected from the group consisting ofFe, Mn, Mg, Zn, Cu, Ni, Co, Mo, V, Cr, Si, B, and Ca. Alternatively,polymers containing, mixed with or complexed with such elements may beformulated using a wide variety of methods that are well known in theart of fertilizer formation. Examples of such alternative methodsinclude, forming an aqueous solution containing molybdate and the sodiumsalt of polymers in accordance with the invention, forming an aqueoussolution which contains a zinc complex of polymers in accordance withthe present invention and sodium molybdate, and combinations of suchmethods. In these examples, the presence of the polymer in soil adjacentgrowing plants would be expected to enhance the availability of theseelements to these growing plants. In the case of Si and B, the elementwould merely be mixed with the polymer rather than having a coordinatemetal complex formation. However, in these cases, the availability ofthese ions would be increased for uptake by growing plants and will betermed “complexed” for purposes of this application.

[0024] The polymers hereof (with or without complexed ions) may be useddirectly as plant growth enhancers. For example, such polymers may bedispersed in a liquid aqueous medium and applied foliarly to plantleaves or applied to the earth adjacent growing plants. It has beenfound that the polymers increase the plant's uptake of bothpolymer-borne metal nutrients and ambient non-polymer nutrients found inadjacent soil. In such uses, plant growth-enhancing amounts ofcompositions comprising the above-defined polymers are employed, eitherin liquid dispersions or in dried, granular form. Thus, application ofpolymer alone results in improved plant growth characteristics,presumably by increasing the availability of naturally occurring ambientnutrients. Typically, the polymers are applied at a level of from about0.001 to about 100 lbs. polymer per acre of growing plants, and morepreferably from about 0.005 to about 50 lbs. polymer per acre, and stillmore preferably from about 0.01 to about 2 lbs.

[0025] In other preferred uses, the polymers may be used to formcomposite products where the polymers are in intimate contact withfertilizer products including but not limited to phosphate-basedfertilizers such as monoammonium phosphate (MAP), diammonium phosphate(DAP), any one of a number of well known N—P—K fertilizer products,and/or fertilizers containing nitrogen materials such as ammonia(anhydrous or aqueous), ammonium nitrate, ammonium sulfate, urea,ammonium phosphates, sodium nitrate, calcium nitrate, potassium nitrate,nitrate of soda, urea formaldehyde, metal (e.g. zinc, iron) ammoniumphosphates; phosphorous materials such as calcium phosphates (normalphosphate and super phosphate), ammonium phosphate, ammoniated superphosphate, phosphoric acid, superphosphoric acid, basic slag, rockphosphate, colloidal phosphate, bone phosphate; potassium materials suchas potassium chloride, potassium sulfate, potassium nitrate, potassiumphosphate, potassium hydroxide, potassium carbonate; calcium materials,such as calcium sulfate, calcium carbonate, calcium nitrate; magnesiummaterials, such as magnesium carbonate, magnesium oxide, magnesiumsulfate, magnesium hydroxide; sulfur materials such as ammonium sulfate,sulfates of other fertilizers discussed herein, ammonium thiosulfate,elemental sulfur (either alone or included with or coated on otherfertilizers); micronutrients such as Zn, Mn, Cu, Fe, and othermicronutrients discussed herein; oxides, sulfates, chlorides, andchelates of such micronutrients (e.g., zinc oxide, zinc sulfate and zincchloride); such chelates sequestered onto other carriers such as EDTA;boron materials such as boric acid, sodium borate or calcium borate; andmolybdenum materials such as sodium molybdate. As known in the art,these fertilizer products can exist as dry powders/granules or as watersolutions.

[0026] In such contexts, the polymers may be co-ground with thefertilizer products, applied as a surface coating to the fertilizerproducts, or otherwise thoroughly mixed with the fertilizer products.Preferably, in such combined fertilizer/polymer compositions, thefertilizer is in the form of particles having an average diameter offrom about powder size (less than 0.001 cm) to about 10 cm, morepreferably from about 0.1 cm to about 2 cm, and still more preferablyfrom about 0.15 cm to about 0.3 cm. The polymer is present in suchcombined products at a level of from about 0.001 g to about 20 g polymerper 100 g phosphate-based fertilizer, more preferably from about 0.1 gto about 10 g polymer per 100 g phosphate-based fertilizer, and stillmore preferably from about 0.5 g to about 2 g polymer per 100 gphosphate-based fertilizer. Again, the polymeric fraction of suchcombined products may include the polymers defined above, or suchpolymers complexed with the aforementioned ions. In the case of thecombined fertilizer/polymer products, the combined product is applied ata level so that the polymer fraction is applied at a level of from about0.001 to about 20 lbs. polymer per acre of growing plants, morepreferably from about 0.01 to about 10 lbs polymer per acre of growingplants, and still more preferably from about 0.5 to about 2 lbs polymerper acre of growing plants. The combined products can likewise beapplied as liquid dispersions or as dry granulated products, at thediscretion of the user. When polymers in accordance with the presentinvention are used as a coating, the polymer comprises at least about0.01% by weight of the coated fertilizer product, more preferably thepolymer comprises at least about 5% by weight of the coated fertilizerproduct, and most preferably comprises at least about 10% by weight ofthe coated fertilizer product.

[0027] Additionally, use of polymers in accordance with the presentinvention increases the availability of phosphorus and other commonfertilizer ingredients and decreases nitrogen volitilization, therebyrendering ambient levels of such plant nutrient available for uptake bygrowing plants. In such cases, the polymer can be applied as a coatingto fertilizer products prior to their introduction into the soil. Inturn, plants grown in soil containing such polymers exhibit enhancedgrowth characteristics.

[0028] Another alternative use of polymers in accordance with thepresent invention includes using the polymer as a seed coating. In suchcases, the polymer comprises at least about 0.01% by weight of thecoated seed, and more preferably comprises at least about 5% by weightof the coated seed, and still more preferably comprises at least about10% by weight of the coated seed.

[0029] In general, the polymers of the invention are made by freeradical polymerization serving to convert selected monomers into thedesired polymers with recurring polymeric subunits. Such polymers may befurther modified to impart particular structures and/or properties. Avariety of techniques can be used for generating free radicals, such asaddition of peroxides, hydroperoxides, azo initiators, percarbonate,per-acid, charge transfer complexes, irradiation (e.g., UV, electronbeam, X-ray, gamma-radiation and other ionizing radiation types), andcombinations of these techniques. Of course, an extensive variety ofmethods and techniques are well known in the art of polymer chemistryfor initiating free-radical polymerizations. Those enumerated herein arebut some of the more frequently used methods and techniques. Anysuitable technique for performing free-radical polymerization is likelyto be useful for the purposes of practicing the present invention.

[0030] The polymerization reactions are carried out in a compatiblesolvent system, namely a system which does not unduly interfere with thedesired polymerization, using essentially any desired monomerconcentrations. A number of suitable aqueous or non-aqueous solventsystems can be employed, such as ketones, alcohols, esters, ethers,aromatic solvents, water and mixtures thereof. Water alone and the lower(C₁-C₄) ketones and alcohols are especially preferred, and these may bemixed with water if desired. In most instances, the polymerizationreactions are carried out with the substantial exclusion of oxygen, andmost usually under an inert gas such as nitrogen or argon. There is noparticular criticality in the type of equipment used in the synthesis ofthe polymers, i.e., stirred tank reactors, continuous stirred tankreactors, plug flow reactors, tube reactors and any combination of theforegoing arranged in series may be employed. A wide range of suitablereaction arrangements are well known to the art of polymerization.

[0031] In general, the initial polymerization step is carried out at atemperature of from about 0° C. to about 120° C. (more preferably fromabout 30° C. to about 95° C. for a period of from about 0.25 hours toabout 24 hours and even more preferably from about 0.25 hours to about 5hours. Usually, the reaction is carried out with continuous stirring.

[0032] After the initial polymerization, the products are recovered andhydrolyzed so as to replace at least certain of the ester-containinggroups on the polymer with alcohol groups, thereby providing thepolymers defined previously. Generally, the hydrolyzing step involvesthe addition of an acid or base to the polymerized product in thepresence of water. Polymers comprising monomers with vinyl ester groups(polymers formed at least in part from A moieties) need to havesufficient base added to neutralize all of the carboxylic acid groupsand form a substantial number of alcohol groups from the precursor vinylester groups. Thereafter, the completed polymer may be recovered as aliquid dispersion or dried to a solid form. It is important to note thatboth acid and base hydrolysis are useful in practicing the presentinvention so that under appropriate conditions, sufficient acid must beadded in order to form a substantial number of alcohol groups.Additionally, in many cases it is preferred to react the hydrolyzedpolymer with an ion such as Fe, Mn, Mg, Zn, Cu, Ni, Co, Mo, V, Cr, andCa to form a coordinate metal complex. Techniques for makingmetal-containing polymer compounds are well known to those skilled inthe art. In some of these techniques, a metal's oxide, hydroxide,carbonate, salt, or other similar compound may be reacted with thepolymer in acid form. These techniques also include reacting a finelydivided free metal with a solution of an acid form of a polymerdescribed or suggested herein. Additionally, the structures of complexesor salts of polymers with metals in general, and transition metals inparticular, can be highly variable and difficult to precisely define.Thus, the depictions used herein are for illustrative purposes only andit is contemplated that desired metals or mixtures of such are bonded tothe polymer backbone by chemical bonds. Alternatively, the metal may bebonded to other atoms in addition to those shown. For example, in thecase of the structure shown herein for the second reactant, there may beadditional atoms or functional groups bonded to the Y. These atomsinclude, but are not limited to, oxygen, sulfur, halogens, etc. andpotential functional groups include (but are not limited to) sulfate,hydroxide, etc. It is understood by those skilled in the art ofcoordination compound chemistry that a broad range of structures may beformed depending upon the preparation protocol, the identity of themetal, the metal's oxidation state, the starting materials, etc.Alternatively, acid hydrolysis may be performed followed by a reactionto form a complex with a previously enumerated metal. In yet anotheralternative method, the polymer may be isolated and subsequentlyformulated in such a way that the hydrolysis reaction occurs in situ, inthe soil or during mixture with a fertilizing composition. In thisalternative method, unhydrolyzed polymer is added to soil or fertilizercompositions of appropriately low or high pH such that when contacted bywater, a microenvironment of low or high pH is produced. It is withinthis microenvironment that hydrolysis occurs and alcohol groups areformed. In the case of Si and B ions, the polymer is merely mixed withthese ions and does not form a coordinate complex. However, theavailability of these ions to growing plants is increased.

[0033] In more detail, the preferred method for polymer synthesiscomprises the steps of providing a reaction mixture comprising at leasttwo different reactants selected from the group consisting of first,second, and third reactants. The first reactant is of the generalformula

[0034] the second reactant is of the general formula

[0035] and the third reactant is of the general formula

[0036] With reference to the above formulae, R₁, R₂ and R₇ areindividually and respectively selected from the group consisting of H,OH, C₁-C₃₀ straight, branched chain and cyclic alkyl or aryl groups,C₁-C₃₀ straight, branched chain and cyclic alkyl or aryl C₁-C₃₀ basedester groups (formate (C₀), acetate (C₁), propionate (C₂), butyrate(C₃), etc. up to C₃₀), R′CO₂ groups, and OR′ groups, wherein R′ isselected from the group consisting of C₁-C₃₀ straight, branched chainand cyclic alkyl or aryl groups; R₃ and R₄ are individually andrespectively selected from the group consisting of H, C₁-C₃₀ straight,branched chain and cyclic alkyl or aryl groups; R₅, R₆, R₁₀ and R₁₁ areindividually and respectively selected from the group consisting of H,the alkali metals, NH₄ and the C₁-C₄ alkyl ammonium groups, Y isselected from the group consisting of Fe, Mn, Mg, Zn, Cu, Ni, Co, Mo, V,Cr, Si, B, and Ca; R₈ and R₉ are individually and respectively selectedfrom the group consisting of nothing (i.e., the groups arenon-existent), CH₂, C₂H₄, and C₃H₆, at least one of said R₁, R₂, R₃ andR₄ is OH where said polymeric subunits are made up of A and B moieties,at least one of said R₁, R₂ and R₇ is OH where said polymeric subunitsare made up of A and C moieties, and at least one of said R₁, R₂, R₃, R₄and R₇ is OH where said polymeric subunits are made up of A, B and Cmoieties.

[0037] Selected monomers and reactants are dispersed in a suitablesolvent system and placed in a reactor. The polymerization reaction isthen carried out to obtain an initial polymerized product having thedescribed recurring polymeric subunits. Thereupon, the initial polymerproduct is hydrolyzed to the alcohol form. Put another away, the generalreaction proceeds by dissolving monomers (e.g., maleic anhydride andvinyl acetate) in a solvent (e.g., acetone). The amount of monomersincorporated can be either equimolar or non-equimolar. A free radicalinitiator is then introduced and copolymerization takes place insolution. After the reaction is complete and substantially all monomerhas been reacted, the resulting solution is a maleic anhydride-vinylacetate copolymer. Of course, if all monomers have not undergonepolymerization, the resulting solution will contain a small portion ofmonomers which do not affect later use of the polymer. The solution isconcentrated and subjected to hydrolysis (either in situ or byperforming a hydrolysis reaction during manufacture) with a sufficientamount of base (e.g., NaOH) in the presence of water. This baseneutralizes a substantial majority of the carboxylic acid groups andconverts a substantial majority of the polymer's acetate groups intoalcohol groups. The anhydride groups are converted to carboxylic acidsodium salt groups arranged in groups of two on the backbone of thepolymer. The resulting copolymer is then isolated by conventionalmethods such as precipitation.

[0038] Again, it is important to note that the aforementioned methodsand procedures are merely preferred methods of practicing the presentinvention and those skilled in the art understand that a large number ofvariations and broadly analogous procedures can be carried out using theteachings contained herein. For example, acid hydrolysis can also beused followed optionally by formation of various derivatives or thehydrolysis may be carried out naturally in soil under sufficientmoisture and pH conditions. The acid hydrolysis isolates the polymers ofthe present invention in a substantially acid form which renders themhighly versatile and useful. These polymers may be used as is (in theacid form) or further reacted with various materials to make saltsand/or complexes. Furthermore, complexes or salts with various metalsmay be formed by reacting the acid form with various oxides, hydroxides,carbonates, and free metals under suitable conditions. Such reactionsare well known in the art and include (but are not limited to) varioustechniques of reagent mixing, monomer and/or solvent feed, etc. Onepossible technique would be gradual or stepwise addition of an initiatorto a reaction in progress. Other potential techniques include theaddition of chain transfer agents, free radical initiator activators,molecular weight moderators/control agents, use of multiple initiators,initiator quenchers, inhibitors, etc. Of course, this list is notcomprehensive but merely serves to demonstrate that there are a widevariety of techniques available to those skilled in the art and that allsuch techniques are embraced by the present invention.

[0039] Another alternative method involves taking an aqueous solutionof, for example, caustic and stirring it in a suitable container. Next,an acetone reaction mixture containing, for example, acetone and acopolymer of maleic anhydride with vinyl acetate is added to the causticsolution. Throughout this addition, the polymer going into the causticsolution will experience a high pH and have the acetate groupshydrolyzed to the alcohol form. In acid-base titrations such as this, atthe point where one reagent is just exhausted, a very sharp pH changeusually takes place with minimal addition of the second reagent.Therefore, in this reaction, just enough acetone-polymer reactionsolution is added to bring the apparent pH of the now final polymerproduct-acetone-water mixture to about 7. At this time, the mixture issubjected to reduced pressure distillation to remove acetone. The resultis an aqueous solution at a neutral pH that contains the desiredpolymer. From this solution, it may be isolated by a variety of ways,including but not limited to precipitation, spray drying, simple drying,and etc. The only side effect of a reaction of this type is that a smallfraction of the polymer is going to contain acetate groups which are nothydrolyzed to alcohol.

[0040] The foregoing description is useful in instances where polymersin accordance with the present invention, upon dissolution in water,give a solution that is alkaline. In many cases, this alkalinity is nota problem as the solution pH can be adjusted to neutral or acidic with asuitable mineral or organic acid. However, the formulation of thispowder into some liquid formulations containing metals is problematic.High-pH solutions of metal salts tend to form insoluble metal hydroxidesthat precipitate and/or exhibit other behaviors that are undesirablefrom the point of view of formulation ease and convenience, as well asnutrient availability. One way to remedy this problem, other than asdescribed in the preceding paragraph, is to add a mineral or organicacid to the aqueous solution of polymer salt in order to bring the pHclose to neutral.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] The following examples set forth techniques for the synthesis ofpolymers in accordance with the invention, and various uses thereof. Itis to be understood that these examples are provided by way ofillustration only and nothing therein should be taken as a limitationupon the overall scope of the invention.

EXAMPLE 1

[0042] Acetone (111 ml), maleic anhydride (20 g), vinyl acetate monomer(19 ml), and the radical source initiator di-tertbutyl peroxide (2.4 ml)were stirred together under inert gas (such as nitrogen or argon) in areactor. The reactor provided included a suitably sized glass sphericalflask equipped with a magnetic stirrer, an inert gas inlet, a contentstemperature measurement device in contact with the contents of theflask, and a removable reflux condenser. This combination of materialswas heated in a hot water bath with stirring at an internal temperatureof about 70° C. for five hours. At that point, the contents of the flaskwere evaporated (by removing the condenser with continued heating) to athick oil, and 100 ml of water was added. Then, 18 g of granular sodiumhydroxide (NaOH) was added to the above dispersion. The resultingmixture was heated again to about 100° C. and allowed to reflux forabout two hours. The mixture was then allowed to evaporate by removal ofthe condenser to a slightly viscous mass. This mass was precipitated byadding the evaporated mixture to about 0.5 liters of ethanol whilestirring was continued. The solids were recovered and then dried. Theresulting product was a white-colored powder. These reactions proceededas follows:

EXAMPLE 2

[0043] This reaction was carried out similarly to that of Example 1.However, in this case the following quantities of ingredients were used:acetone (50 ml), maleic anhydride (44 g), vinyl acetate monomer (42 ml),and di-tertbutyl peroxide (8.3 ml). This mixture was heated in a hotwater bath with stirring at an internal temperature of about 70° C. forfive hours. The contents of the reactor flask were then evaporated to athick oil and 100 ml of water was added. Next, 57 g granular NaOH wasadded. This mixture was heated again to about 100° C. and allowed toreflux for about one hour. After refluxing, the mixture evaporated to aslightly viscous mass. This mass was precipitated by adding it, withstirring to 0.9 liters of ethanol. The solids were then recovered anddried. The resulting product was a tan-colored powder.

EXAMPLE 3

[0044] This reaction was also carried out as in Example 1. However, thefollowing quantities of ingredients were used: acetone (273.0 ml),maleic anhydride (49 g), vinyl acetate monomer (46 ml), and di-tertbutylperoxide (5.9 ml). This mixture was heated in a hot water bath withstirring at an internal temperature of about 70° C. for five hours. Thecontents of the flask were then evaporated into a thick oil (once againby removing the condenser), and 250 ml of water was added. Following thewater addition, 63 g of granular NaOH was added. The resulting mixturewas heated to about 100° C. again, and allowed to reflux for about onehour. This mixture was then evaporated to a slightly viscous mass. Themass was precipitated with stirring into about 2 liters of ethanol.Solids were recovered and dried and the product was a very bright whitepowder.

EXAMPLE 4

[0045] In this example, copper was complexed with the polymer isolatedin Example 1. Five grams of the Example 1 polymer was mixed with 50 g(dry weight) of ion exchange resin (strong acid macro reticular, 4.9meq/gram dry) which had been soaked in water until the mixture wasfluid. The acid form of the polymer was then washed out with severalaliquots of water. The resultant water-polymer mixture was then mixedwith 6 g of CuSO₄ pentahydrate. The aqueous solution containing thecopper complex was then evaporated to dryness and the material wascollected.

EXAMPLE 5

[0046] One gram of the polymer prepared and isolated in Example 1 wasdissolved into 20 ml of room temperature water. 1.3 g sodium bisulfatewas added to this dispersion with stirring. While stirring wascontinued, 0.5 g of ferric sulfate (Fe₂(SO₄)₃) tetrahydrate was addedslowly with stirring. This product was isolated by evaporating the waterfrom the solution to dryness. Thereafter, the isolated dry material wascollected. The resultant product was an iron complex of the polymer ofExample 1.

EXAMPLE 6

[0047] In this example, 1 g of the polymer prepared and isolated inExample 1 was added to 20 ml of room temperature water. Sulfuric acid(98%) was added to the dispersion with stirring, until the pH dropped toabout 2. 1.5 g of manganese dichloride tetrahydrate was added slowly tothe dispersion with vigorous stirring. The material (a manganese complexof the Example 1 polymer) was then evaporated to dryness and thematerial was collected.

EXAMPLE 7

[0048] Five grams of the polymer prepared and isolated in Example 1 wasdissolved in 100 ml of water. Sulfuric acid (98%) was added until the pHdropped to about 2. 7 g of zinc sulfate heptahydrate was added slowlywith vigorous stirring to the dispersion. The resulting solution had theproduct (a zinc complex of the Example 1 polymer) isolated byevaporating the water to dryness and was collected thereafter.

EXAMPLE 8

[0049] Water (30 g), and maleic anhydride (20 g) is put into the reactorwith stirring under inert gas, such as nitrogen or argon. During thistime, the anhydride is converted to the acid form. Di-tertbutyl peroxide(2.4 ml) is added to the flask. The resulting mixture is heated andrefluxed until the reflux head temperature gradually rises to about 100°C. At this point, vinyl acetate monomer (19 ml) is gradually added tothe reaction at about the same rate that it is consumed. The reaction iscarried out until substantially all monomer is consumed. The product ofthis synthesis is then hydrolyzed as in Example 1. This exampledemonstrates that the preferred polymerization may be carried out in anaqueous medium.

EXAMPLE 9

[0050] The product of the reaction described in Example 8 is refluxedovernight at about 100° C. and then subjected to a short-pathdistillation under inert atmosphere in order to remove the acetic acidhydrolysis product. Due to the high temperature and high productconcentration, lactone formation is minimized, and the fraction ofdicarboxylic acid functional groups that are available is maximized. Thedesired product is isolated by spray-drying the aqueous solution to givea white amorphous powder.

EXAMPLE 10

[0051] This example is similar to that described in Example 8; however,water is replaced with a 1:1 (w/w) mixture of water and ethanol. 20 g ofmaleic anhydride is added to this mixture. Next, di-tertbutyl peroxide(2.4 ml) is added to the reactor and the resulting mixture is heated toreflux until the reflux head temperature rises to about 100° C. Vinylacetate monomer is then gradually added to the reaction at about thesame rate it is consumed. Once again, 19 ml of vinyl acetate monomer isused. The reaction is carried out until substantially all of the monomeris consumed. The resulting product is then refluxed overnight andsubjected to a short-path distillation under inert atmosphere in orderto remove the acetic acid hydrolysis product. Once again, due to thehigh temperature and high product concentration, lactone formation isminimized and the fraction of dicarboxylic acid functional groups ismaximized. The desired product is then isolated by spray-drying theaqueous solution to give a white amorphous powder.

EXAMPLE 11

[0052] This Example demonstrates that the polymerization may be carriedout using UV free radical initiation instead of peroxide. Water (30 g)and maleic anhydride (20 g) is mixed in the reactor under inert gas. A10 watt lamp emitting UV radiation at the 190-210 nm wavelength range isimmersed in the reaction vessel. The mixture is heated to reflux untilthe reflux head temperature gradually rises to about 100° C., at whichpoint 19 ml of vinyl acetate monomer is gradually added to the reactionat about the same rate as it is consumed. The reaction is carried outuntil substantially all of the monomer is consumed. Once synthesis(copolymerization) is substantially complete, the resultant product ishydrolyzed as in Example 1.

EXAMPLE 12

[0053] In this example, polymerization is carried out using UV freeradical initiation in a mixture of organic solvent and water. Theexperiment is carried out as in Example 11, but water is replaced with a1:1 (w/w) mixture of water and ethanol. The isolation and hydrolysisprocedures are substantially the same as those used in Examples 8 and 9.

EXAMPLE 13

[0054] In this example, the procedure of Example 8 is carried out exceptthat 1 ml of hydrogen peroxide (30% w/w) is used instead of di-tertbutylperoxide.

EXAMPLE 14

[0055] This example demonstrates acid hydrolysis in an aqueous medium.To the product of the reaction described in Example 8, 0.2 g 98% ofsulfuric acid is added and the mixture is refluxed overnight at about100° C. Next, the mixture is subjected to a short-path distillationunder inert gas to remove the acetic acid hydrolysis product. Due to theacidity, high temperature and high product concentration, lactoneformation is minimized, and the fraction of dicarboxylic acid functionalgroups is maximized. The product is isolated by spray drying the aqueoussolution to give a white amorphous powder.

EXAMPLE 15

[0056] An aqueous solution composed of 40 g water, 11.6 g maleic acidand 8.1 g zinc oxide is formed. The oxide slowly reacts and dissolves togive zinc maleate derivative solution. This is used as a monomer sourcein a polymerization such as that described in Example 8 where equimolaramounts of maleate and vinyl acetate were used. After that, a hydrolysisis performed using the procedures described in Example 14. The reactionproceeded as follows:

EXAMPLE 16

[0057] An aqueous solution composed of 40 g water, 11.6 g maleic acid,and 11.5 g manganese carbonate is prepared. The carbonate slowly reactsand dissolves to give manganese maleate derivative solution. Thismanganese maleate solution is used as a monomer source in apolymerization such as that described in Example 8, wherein equimolaramounts of maleate and vinyl acetate were used. After that, a hydrolysisis performed using the procedures described in Example 14. The reactionproceeded as follows:

EXAMPLE 17

[0058] An aqueous solution composed of 40 g water, 11 .g maleic acid,and 5.6 g very fine iron dust is formed. The metal slowly reacts anddissolves to give iron maleate derivative solution. This solution isused as a monomer source in a polymerization reaction such as thatdescribed in Example 8, wherein equimolar amounts of maleate and vinylacetate were used. After that, a hydrolysis is performed using theprocedures described in Example 14. This reaction proceeded as follows:

EXAMPLE 18

[0059] A continuous reactor is provided including an in-line motionlesstube mixer, pumps, thermostatted tubes, and associated valves, fittings,and controls. Maleic anhydride (50% w/w in acetone), vinyl acetate anddi-tertbutyl peroxide are pumped into the in-line tube mixer and theninto the thermostatted tube. The mixture's residence time in the tube isabout 3 hours. The tube temperature is about 70° C. The flow rates are:maleic anhydride solution—100 g/min; vinyl acetate—43 g/min; anddi-tertbutyl peroxide—3 g/min. Hydrolysis is performed using theprocedures described in Example 14.

EXAMPLE 19

[0060] Aqueous dispersions containing 10, 50 and 100 ppm of the copper,manganese and zinc copolymers formed in Examples 4, 6 and 7 were appliedto the foliage of plum, maple and sweetgum trees, respectively, in orderto obtain substantially uniform foliage coverage. Prior to thisapplication, the trees visually exhibited characteristic deficiencysymptoms for each of the three micronutrients. This treatment alleviatedthe visual symptoms of the micronutrient deficiency in about 7-10 days.

EXAMPLE 20

[0061] Bluegrass was treated with aqueous dispersions of the ironcopolymer from Example 5 (20, 50 and 100 ppm concentrations of ironcopolymer) and compared to an untreated control which received no ironcopolymer. These foliar iron treatments were applied at three differenttimes as pretreatments before bluegrass was harvested. Photos of theplants were taken two weeks after the last treatment. The results(Table 1) clearly show that the bluegrass responded to the ironcopolymer application. The total harvest weights for each of the threeiron copolymer bluegrass test groups were at least twice that of thecontrol bluegrass. As the amount of copolymer applied increased, harvestweight also increased. TABLE 1 Bluegrass Response to VaryingConcentrations of Fe Copolymer Harvest Wts (g) Fe CopolymerConcentration Applied Harvest 0 ppm 25 ppm 50 ppm 100 ppm 1 0.3 1.6 1.82.1 2 1.8 2.9 2.1 2.0 3 1.4 2.5 3.6 3.9 Total 3.5 7.0 7.5 8.0

[0062] In this example, the effect of iron copolymer treatment onLisintus was determined. The iron copolymer of Example 5 was used forthis experiment. The first control group of plants received no ironcopolymer treatment, the second group was foliarly treated with anaqueous dispersion containing 50 ppm of the iron copolymer on threedifferent occasions before harvest, and the third group was similarlytreated with an aqueous dispersion containing 100 ppm iron copolymerthree times before harvest. The Lisintus was harvested and analyzed (bydigestion followed by atomic absorption spectroscopy) for ironconcentration, and by SPAD meter to determine photosynthetically activechlorophyl levels. The results of this experiment are given in Table 2which shows that application of iron copolymer resulted in a higher ironconcentration in the Lisintus leaves. However, the amount of ironcopolymer applied to the Lisintus did not have an appreciable effect onultimate iron concentration (i.e. SPAD meter readings between Lisintustreated with 50 ppm iron copolymer and 100 ppm iron copolymer did notdiffer significantly). Therefore, the most efficient treatment may occurat levels below 50 ppm. TABLE 2 Iron Concentration and SPAD MeterReadings of Lisintus Leaves Treated with Foliar Applications of IronCopolymer Treatment Fe Uptake (ppm) SPAD Meter Readings Control 146 29.5 50 ppm 276 63.7 100 ppm 309 64.1

EXAMPLE 22

[0063] In this experiment, different amounts of the copolymer formed inExample 1 were used in conjunction with phosphate fertilizer in soil, inorder to test the effect of using the polymer with the fertilizer. Inparticular, the test was conducted on ryegrass grown in growth bags. Thegrowth bags contained soil, water and a conventional, commerciallyavailable 8-14-9 N PK liquid fertilizer. One growth bag (the control)had no copolymer added. One bag labeled 0.5× was treated with afertilizer mixture containing 25 ppm of the copolymer (the copolymer wasadded to the liquid fertilizer prior to addition thereof to the growthbags). The bag labeled 1× was treated with a liquid fertilizer mixturecontaining 50 ppm of copolymer. The fertilizer solution in the growthbags were replenished uniformly on an as-needed basis. After the grasswas harvested, it was dried and weighed. Results of this experiment aregiven in Table 3 which shows no response to the 0.5× copolymerapplication. The 1× copolymer application resulted in a 25% increase indry weight. TABLE 3 Effects of Copolymer with Liquid Fertilizer onResulting Plant Growth Treatment Average Shoot Weight lX Copolymer andLiquid Fertilizer 33.0 .5X Copolymer and Liquid Fertilizer 25.0Control-Liquid Fertilizer Only 24.9

EXAMPLE 23

[0064] In this test, the copolymer from Example 1 was tested withphosphate fertilizers in high phosphate-fixing soils in corn growthtests. The test was designed to determine the effect of the copolymer onthe plant availability of phosphate based fertilizer in the soil. Forthis experiment, monoammonium phosphate (MAP) was tested although it isunderstood that similar results would occur with any phosphate basedfertilizer.

[0065] Two soils were utilized in the study, an acid soil (pH 4.5-4.7)from Sedgewick County, Kans. and a calcareous soil (pH 8.0-8.3) from thevicinity of Tribune, Kans. The acid soil is high in available P butowing to the high exchangeable Al and Fe content of the soil, Pavailability is limited. The calcareous soil was lower in available P.

[0066] Containers (flats) approximately 75 cm×40 cm were used for thestudy. These flats held approximately 8 kg of soil filled to a depth ofapproximately of 7.5 cm, and allows planting in rows with band placementof the fertilizer material, beside the row or in seed contact ifdesired. Multiple rows within each container were used as replications.The containers served as individual treatment for each crop and wererotated to eliminate any possible variables of light and/or temperature.

[0067] Corn was used as the test crop. The seeds were planted in rows,thinned to a constant population per row. Only a single variety of cornwas used for each crop. Corn was taken to approximately the 6-leaf stagebefore the whole plant was harvested for dry weight and plantcomposition analysis. In the corn test, four plants per row perreplication were used, thinned back from ten plants.

[0068] Conventional Cargill MAP fertilizer was used, with the fertilizerbeing coated with the copolymer product of Example 1 at rates of 1 gcopolymer/100 g MAP (P1×) and 2 g copolymer/100 g MAP (P2×). The MAPparticles were sized prior to copolymer application to insure that theindividual particles were of approximately the same size. In allinstances, a single rate of application of 20 ppm phosphorus calculatedas P₂O₅ was employed. In addition, a no-phosphorus control was alsoincluded in the study for each crop on each soil. Other nutrients weresupplied at constant rates.

[0069] The fertilizer-copolymer MAP product was applied in a bandedfashion with a constant number of phosphate material particles utilizedper row (63 particles per each 10 inch row section). This procedureplaced the experimental products close to the rows for maximumavailability in the phosphate-fixing conditions, and allowed comparisonof the effect of the copolymer with each phosphorus fertilizer.

[0070] After harvesting, the plants were tested for dry weight,phosphorus concentration and phosphorus uptake. SAS was utilized toanalyze variance of the data. TABLE 4 Phosphorus MaterialsEvaluation-Corn Material Dry Wt. (g) P. Concentration (%) P UptakeControl 5.18 0.827 43.2 P1X 8.90 0.996 88.7 P2X 9.55 1.043 99.6LSD_(.05) 2.47 0.177 31.8

EXAMPLE 24

[0071] In this test, the effects of polymers on nitrogen volitilizationwas tested. A urea was sized by screening to a uniform size and wastreated to form a 5% by weight coating of a polymer in accordance withthe present invention. The coating was prepared by solubilizing 5 gramsof polymer in 3 ml of water. The mixture was then added uniformly to 95g of urea. To the mixture, 7 g of clay was added which dried the mixtureand provided a clay coating. The mixture was then applied to soil forcomparison. There were two polymers tested, one which was 50% calciumand 50% hydrogen saturated and the other which was 100% calciumsaturated. Each of these polymer mixtures were compared to an untreatedurea. Soil samples were taken and cumulative nitrogen losses weredetermined after 16 days.

[0072] As shown in Table 5, coating the urea with clay or a polymer andclay combination greatly reduced nitrogen volatilization. Untreated urealost 37.4% of its total nitrogen. The polymers, calcium/hydrogenmixtures and calcium alone, lost only 20.6% and 19.5% respectively.Unexpectedly, the polymer combination significantly reduced nitrogenvolatilization. TABLE 5 Ammonia Loss as a Percentage of Total NitrogenApplied Aver- Treatment Replicate 1 Replicate 2 Replicate 3 age Urea33.3 41.3 37.7 37.4 Urea/Clay/5% Polymer 19.0 19.3 23.7 20.6 50% H, 50%Ca saturated Urea/Clay/5% Polymer 17.1 21.7 19.5 19.5 100% Ca saturated

EXAMPLE 25

[0073] This experiment determined the effects of polymers in accordancewith the invention on phosphorus fertilizer availability. An acid soil(pH 4.7) and a calcareous soil (pH 7.8) treated as in Example 23 werecollected. These soils were chosen for their P fixing characteristics,preformed by Fe and Al in the acid soil and Ca in the calcareous soil.All treatments involved four replication. Soil samples were collectedfrom the area of banded P beside the corn row after the plants had beenharvested. The phoshporus material was MAP (although it is understoodthat all fertilizers should have similar results) with and without anexperimental coating of 1.0% on the exterior of the MAP particles. Thecoating was prepared using the procedures described above in Example 24.Phosphorus rates were 5, 10 and 20 ppm P205 banded beside the seed (1inch to the side, 1 inch below) of corn in flats containing 7 kilogramsof soil. Composited cores from each treatment were processed andanalyzed using conventional testing procedures. A single weak acidextractant (Bray P-1) was utilized for both the acid and calcareoussoils. The P fertilizer had been in contact with the soil forapproximately 5 weeks at the time of sampling.

[0074] Results of this experiment are given below in Table 6. CoatingMAP with the experimental product produced consistently higher soil testP values indicating that the extractability of the P was increased.Therefore, normal soil P fixation had not progressed as rapidly in thepresence of the polymer. The results from the acid soil displayed moredifferentiation that those of the calcareous soil, perhaps due to thetendency of the weak Bray extractant to react with free calciumcarbonate in the calcareous soil. Plant growth data also demonstratedsimilar indications of greater P availability.

[0075] Thus, polymers in accordance with the present invention havesignificant effects on P availability from ammonium phosphatefertilizers. Furthermore, these polymers may be of substantial value inimproving P use efficiency from applied fertilizers on both acid andcalcareous soils with P fixation capacities. TABLE 6 Polymer Effects onSoil Test P Soil Bray-1 P Treatment Concentrations ppm P No P Control,Acid Soil 76 5 ppm P205, MAP Control, Acid Soil 121 10 ppm P205, MAPControl, Acid Soil 117 20 ppm P205, MAP Control, Acid Soil 151 5 ppmP205, MAP Experimental, Acid Soil 195 10 ppm P205, MAP Experimental,Acid Soil 190 20 ppm P205, MAP Experimental, Acid Soil 220 LSD 0.10,Acid Soil 26 No P Control, Calcareous Soil 76 5 ppm P205, MAP Control,Calcareous Soil 96 10 ppm P205, MAP Control, Calcareous Soil 110 20 ppmP205, MAP Control, Calcareous Soil 156 5 ppm P205, MAP Experimental,Calcareous Soil 164 10 ppm P205, MAP Experimental, 159 Calcareous Soil20 ppm P205, MAP Experimental, 102 Calcareous Soil LSD 0.10 CalcareousSoil 38

We claim:
 1. A method of enhancing the growth of plants comprising thestep of applying to said plants or the earth adjacent said plants agrowth-enhancing amount of a composition comprising recurring polymericsubunits each made up of at least two different moieties individuallyand respectively taken from the group consisting of A, B, and Cmoieties, or recurring C moieties, wherein moiety A is of the generalformula

moiety B is of the general formula

and moiety C is of the general formula

wherein R₁, R₂ and R₇ are individually and respectively selected fromthe group consisting of H, OH, C₁-C₃₀ straight, branched chain andcyclic alkyl or aryl groups, C₁-C₃₀ straight, branched chain and cyclicalkyl or aryl C₁-C₃₀ based ester groups (formate (C₀), acetate (C₁),propionate (C₂), butyrate (C₃), etc. up to C₃₀), R′CO₂ groups, and OR′groups, wherein R′ is selected from the group consisting of C₁-C₃₀straight, branched chain and cyclic alkyl or aryl groups; R₃ and R₄ areindividually and respectively selected from the group consisting of H,C₁-C₃₀ straight, branched chain and cyclic alkyl or aryl groups; R₅, R₆,R₁₀ and R₁₁ are individually and respectively selected from the groupconsisting of H, the alkali metals, NH₄ and the C₁-C₄ alkyl ammoniumgroups, Y is selected from the group consisting of Fe, Mn, Mg, Zn, Cu,Ni, Co, Mo, V, Cr, Si, B, and Ca; R₈ and R₉ are individually andrespectively selected from the group consisting of nothing, CH₂, C₂H₄,and C₃H₆, at least one of said R₁, R₂, R₃ and R₄ is OH where saidpolymeric subunits are made up of A and B moieties, at least one of saidR₁, R₂ and R₇ is OH where said polymeric subunits are made up of A and Cmoieties, and at least one of said R₁, R₂, R₃, R₄ and R₇ is OH wheresaid polymeric subunits are made up of A, B and C moieties.
 2. Themethod of claim 1, said polymer being applied at a level of from about0.001 lbs. to about 100 lbs. polymer per acre of said growing plants. 3.The method of claim 1, said polymer being in liquid dispersion.
 4. Themethod of claim 1, said polymer being in granular form.
 5. The method ofclaim 1, said polymer being in intimate mixture with a fertilizer. 6.The method of claim 5, said fertilizer being selected from the groupconsisting of phosphate-based fertilizers, fertilizers containingnitrogen, phosphorous, potassium calcium, magnesium, sulfur, boron, ormolybdenum materials, fertilizers containing micronutrients, and oxides,sulfates, chlorides, and chelates of such micronutrients.
 7. The methodof claim 5, said polymer and fertilizer being co-ground together.
 8. Themethod of claim 5, said polymer being applied to the surface of saidfertilizer.
 9. The method of claim 5, said fertilizer being in the formof particles having an average diameter of from about powder size toabout 10 cm.
 10. The method of claim 5, said polymer being present insaid fertilizer product at a level of from about 0.001 g to about 20 gpolymer per 100 g fertilizer.
 11. The method of claim 1, said polymerbeing complexed with an ion.
 12. The polymer of claim 11, said ion beingselected from the group consisting of Fe, Mn, Mg, Zn, Cu, Ni, Co, Mo, V,Cr, Si, B, and Ca.
 13. A method of enhancing the growth of plantscomprising the step of applying to said plants or to the earth adjacentsaid plants a growth-enhancing amount of a fertilizer product, saidfertilizer product comprising a fertilizer in intimate contact with apolymer comprising recurring polymeric subunits each made up of at leasttwo different moieties individually and respectively taken from thegroup consisting of A, B, and C moieties, or recurring C moieties,wherein moiety A is of the general formula

moiety B is of the general formula

and moiety C is of the general formula

wherein R₁, R₂ and R₇ are individually and respectively selected fromthe group consisting of H, OH, C₁-C₃₀ straight, branched chain andcyclic alkyl or aryl groups, C₁-C₃₀ straight, branched chain and cyclicalkyl or aryl C₁-C₃₀ based ester groups (formate (C₀), acetate (C₁),propionate (C₂), butyrate (C₃), etc. up to C₃₀), R′CO₂ groups, and OR′groups, wherein R′ is selected from the group consisting of C₁-C₃₀straight, branched chain and cyclic alkyl or aryl groups; R₃ and R₄ areindividually and respectively selected from the group consisting of H,C₁-C₃₀ straight, branched chain and cyclic alkyl or aryl groups; R₅, R₆,R₁₀ and R₁₁ are individually and respectively selected from the groupconsisting of H, the alkali metals, NH₄ and the C₁-C₄ alkyl ammoniumgroups, Y is selected from the group consisting of Fe, Mn, Mg, Zn, Cu,Ni, Co, Mo, V, Cr, Si, B, and Ca; R₈ and R₉ are individually andrespectively selected from the group consisting of nothing, CH₂, C₂H₄,and C₃H₆, at least one of said R₁, R₂, R₃ and R₄ is OH where saidpolymeric subunits are made up of A and B moieties, at least one of saidR₁, R₂ and R₇ is OH where said polymeric subunits are made up of A and Cmoieties, and at least one of said R₁, R₂, R₃, R₄ and R₇ is OH wheresaid polymeric subunits are made up of A, B and C moieties.
 14. Themethod of claim 13, said polymer being applied at a level of from about0.001 lbs. to about 100 lbs. polymer per acre of said growing plants.15. The method of claim 13, said fertilizer product being a liquiddispersion of said fertilizer and said polymer.
 16. The method of claim13, said fertilizer product being a granulated mixture of saidfertilizer and said polymer.
 17. The method of claim 13, said fertilizerbeing selected from the group consisting of phosphate-based fertilizers,fertilizers containing nitrogen, phosphorous, potassium calcium,magnesium, sulfur, boron, or molybdenum materials, fertilizerscontaining micronutrients, and oxides, sulfates, chlorides, and chelatesof such micronutrients.
 18. The method of claim 13, said fertilizerbeing in the form of particles having an average diameter of from aboutpowder size to about 10 cm.
 19. The method of claim 13, said polymerbeing present in said fertilizer product at a level of from about 0.001g to about 20 g polymer per 100 g fertilizer.
 20. The method of claim13, including the step of applying said fertilizer product to thefoliage of said plants.
 21. The method of claim 13, including the stepof applying said fertilizer product to the earth adjacent said plants.22. The method of claim 13, said polymer being complexed with an ion.23. The method of claim 22, said ion being selected from the groupconsisting of Fe, Mn, Mg, Zn, Cu, Ni, Co, Mo, V, Cr, Si, B, and Ca.